Activating mutations of the AKT1 gene (Glu17Lys and Glu49Lys) are associated in a small number of cases with breast cancers, head and neck squamous cell carcinomas, endometrial cancers, non-small-cell lung cancers, renal cancers, and appendix cancers, the latter of which are occasionally reported in low-grade appendiceal mucinous neoplasms [76]. The gene discussed is AKT1; the disease is breast cancer.